1. Field of the Invention
The present invention relates in general to a device for detachably attaching an implement, for example a bucket, to construction equipment, such as power excavators or loaders, and, more particularly, to a structural improvement in such a device for rapidly attaching the implement to an implement mount link of the construction equipment and thereby easily changing the implements of the construction equipment.
2. Description of the Prior Art
In typical construction equipment such as power excavators, booms, arms and the like, which are operated by their actuators, are mounted to the car body of the construction equipment. In addition, various implements such as buckets are selectively attached to an end of the arm. These implements are selectively attached to the arm as required by working conditions of the construction equipment.
A variety of devices for detachably attaching the implements to construction equipment have been proposed and used. Representative examples of the above devices are shown in FIGS. 1 and 2A-2D respectively.
In the typical implement attaching device shown in FIG. 1, the opposite side ends of an implement mount link 106 are mounted to their associated pin holes 102 and 103, which are formed in the opposite front ends of an arm 101, by means of pins 107 respectively. The link 106 is thus mounted to the arm 101. The opposite side ends of the link 106 are provided with lugs 104 and 105 respectively, each lug 104, 105 having a horizontal tube 111, 111'. The horizontal tubes 111 and 111' of the lugs 104 and 105 are inserted in the associated tube holes 110 of a pair of bottom brackets 109 provided on the rear wall of a bucket 108. The rear wall of the bucket 108 also includes a top bracket 113 having a hook hole 112. A pin 115 is coupled to a lever 114 mounted to the link 106. The pin 115 is inserted in the hook hole 112, thus to detachably attach the bucket 108 to the link 106. In the above device, the bucket 108 can be attached to or detached from the link 106 by handling the lever 114 right and left.
However, the above device has a problem in that a complicated structure, including the top and bottom brackets, should be formed on the rear wall of the implement for detachably attaching the implement to the link. In addition, the sizes of the holes formed in the brackets of the implement are somewhat larger than the diameters of their associated pins of the link in order to let the pins move freely in the holes. However, the pins can not help playing in the holes due to the size difference between the pins and the holes. As the pins play in the holes as described above, the pins may break if they are subject to a sudden impact load while the construction equipment is performing work. In this regard, a serious problem may be caused in the durability of the above device.
In the typical implement attaching device shown in FIG. 2, a link 118 is coupled to an arm 116 by means of a pin 117. The opposite side ends of the link 118 are provided with levers 120. A key 119 which moves up and down in cooperation with movement of the levers 120 passes through the hole 123 of a bucket 121 after passing through the hole 122 of the link 118, thus to attach the bucket 121 to the link 118. The horizontal movement of the bucket 121 relative to the link 118 can be restricted by a pair of stoppers 124 formed on the opposite sides of the rear wall of the bucket 121. The detachable attachment of the bucket 121 relative to the link 118 is achieved by handling the levers 120 right and left.
However, the above implement attaching device has a problem in that it is difficult to separately handle the levers provided on the opposite sides of the link when the bucket is detached from the link. In addition, the above key projects out of the bucket so that the key may be easily broken due to outside impact applied thereto. When the key is suddenly broken during operation of the construction equipment, the bucket is separated from the arm and causes a safety accident.
U.S. Pat. No. 3,272,264 and Japanese Patent Laid-open No. Sho. 58-98532 disclose typical implement attaching devices. However, the above implement attaching devices have a problem in that each of them has a complicated linkage and a separate hydraulic cylinder as a power source. Both the complicated linkage and the hydraulic cylinder increase the cost of the devices.
Korean Patent Appln. No. 12146, which was filed on June, 1993 by this applicant, discloses an implement attaching device.
In the above Korean device, a link is hinged to an arm while the rear wall of the implement is provided with top and bottom guiders which support the top and bottom of the link respectively. A predetermined gap is defined between the top guider and the top of the link. The device also includes implement attaching means of the pantograph type which is received in the above gap and used for detachably attaching the implement to the link.